The overall objective of this work is to explain the mechanism of action of the bacterial ribosome in terms of the chemical structures of its component macromolecules, and to understand the chemical basis of the mutual interaction of these components. Specifically, we are presently directing our efforts toward (1) Elucidation of the role of rRNA in translation (2) Obtaining information about the topography of rRNA and its contact sites with ribosomal proteins within the ribosome (3) Physical and chemical studies of the perturbation of rRNA structure by ribosomal proteins, (4) Determination of the nucleotide sequence of genes for 16S and 23S rRNA.